60Co-γ Irradiation-Induced Shift and Polarity Reversal in the Triboelectric Series of Poly(ether sulfone)s

The sensitivity of triboelectric nanogenerators (TENGs) to the surface charge density highlights the significance of triboelectric materials and their modifications. Efforts have been directed toward developing effective strategies for increasing the surface charge density, expanding the potential applications of TENGs. This study proposes the use of irradiation technology for grafting to modify the electron-donating capability of poly(ether sulfone) (PES), thereby affording a dual benefit of enhancing the surface charge density and inducing a shift in the position of PES from negative to positive within the triboelectric series. The TENG based on grafted PES has resulted in a significant 3-fold increase in surface charge density compared to that of pristine PES, reaching 263 μC m-2. The surface charge density can be further increased to 502 μC m-2 through charge pumping. Notably, irradiation technology presents advantages over chemical grafting methods, particularly in terms of sustainability and environmental friendliness. This innovative approach shows great potential in advancing the domain of TENGs.

Achieving bi-directional conduction block during catheter ablation is not enough to prevent recurrence of cavo-tricuspid isthmus dependant atrial flutter: Role of subclinical conduction

BACKGROUND

Achieving bi-directional conduction block, as assessed by differential pacing and change in activation along tricuspid annulus (TA), across the cavo-tricuspid isthmus (CTI), is considered a satisfactory end point during catheter ablation of atrial flutter (AFL).

AIM

To assess role of subclinical conduction by observing polarity reversal of local bipolar signals from RS to QR pattern lateral to the line of ablation, in predicting recurrence of CTI dependant AFL after ablation in patients with bidirectional conduction block.

METHOD AND RESULTS

Of 683 patients undergoing ablation of CTI dependent AFL, 73 (10.6%) patients underwent redo flutter ablation and were evaluated further. The mean age was 60.8 years and 51% were males. Evidence of bidirectional block by differential pacing and change is activation along multipolar catheter and reversal of local bipolar signals from RS to QR pattern lateral to the line of ablation, during the 1st and subsequent procedure, were studied. 60% patients had confirmed bidirectional block of which 71% had lack of voltage reversal, at the end of 1st procedure. All patients with bidirectional block with lack of reversal of bipolar signals, after the first procedure had recurrence of AFL whereas only 3/11 (27%) people with bidirectional block and with absence of subclinical conduction had recurrence of AFL.

CONCLUSION

Achieving bidirectional conduction block is not sufficient to prevent recurrence of AFL after CTI ablation. Reversal of local bipolar signals, from RS to QR pattern along with achieving bidirectional conduction delay would reduce recurrence of AFL, post ablation.

Plasticity of the spinal glymphatic system in male SD rats with painful diabetic neuropathy induced by type 2 diabetes mellitus

The glymphatic system is a recently discovered glial‐dependent macroscopic interstitial waste clearance system that promotes the efficient elimination of soluble proteins and metabolites from the central nervous system. Its anatomic foundation is the astrocytes and aquaporin‐4 (AQP4) water channels on the endfeet of astrocytes. The aim of this study is to evaluate the plasticity of the spinal glymphatic system in male SD rats with painful diabetic neuropathy (PDN) induced by type 2 diabetes mellitus. PDN rats were modeled under a high‐fat and high‐glucose diet with a low dose of streptozotocin. MRI was applied to observe the infiltration and clearance of contrast to indicate the functional variability of the glymphatic system at the spinal cord level. The paw withdrawal threshold was used to represent mechanical allodynia. The numerical change of glial fibrillary acidic protein (GFAP) positive astrocytes was assessed and the polarity reversal of AQP4 protein was measured by immunofluorescence. As a result, deceased contrast infiltration and clearance, enhanced mechanical allodynia, increased number of GFAP positive astrocytes, and reversed polarity of AQP4 protein were found in the PDN rats. The above molecular level changes may contribute to the impairment of the spinal glymphatic system in PDN rats. This study revealed the molecular and functional variations of the spinal glymphatic system in PDN rats and for the first time indicated that there might be a correlation between the impaired spinal glymphatic system and PDN rats.

Migration and Removal of Labile Cadmium Contaminants in Paddy Soils by Electrokinetic Remediation without Changing Soil pH

Electrokinetic remediation (EKR) is a viable, advanced cleaning strategy that can permanently reduce the toxicity of soil contaminants. However, EKR is prone to causing changes in soil pH. The negative impacts must be minimized if field-scale application is to be realized. In this study, EKR with polarity reversal was used to avoid soil pH polarization and to clean up cadmium (Cd)-contaminated paddy soils. Results showed that Cd desorbed from oxidizable and residual fractions to labile and easily available parts. Soil moisture content above 0.35 g g⁻¹ was conductive to achieving the desirable Cd-migration rate. The exchangeable Cd phase eventually migrated from both ends of that soil compartment towards the intermediate. Moreover, the addition of citric acid at the concentration of 0.1 mol L⁻¹ was an effective enhancement strategy. The methodology enriched Cd contaminants to specific sites. The technology can be used for electrokinetic-assisted phytoremediation during the rice growing period. Hyperaccumulator is planted in the intermediate area to remove the Cd contaminants. On the other hand, Cd removal is achieved in the region close to the electrodes. The present study provides a theoretical basis for in situ remediation. It has a wider significance for field-scale application.

Descriptive Role of Pt/PtOx Ratio on the Selective Chlorine Evolution Reaction under Polarity Reversal as Studied by Scanning Electrochemical Microscopy

This study investigated competing chlorine evolution reaction (ClER) and oxygen evolution reaction (OER) on Pt electrodes under variable polarity reversal intervals (±16.7 mA cm^-2, 30-600 s) in the context of distinctive roles of Pt(0) and PtO_x on the surface in dilute (0.1 M) NaCl solutions. The substrate generation/tip collection mode of scanning electrochemical microscopy (SECM) quantified the current efficiency (CE) of ClER with a large tip-to-substrate distance (>500 μm) to avoid intervention of bubbles and spatial variations. Surface interrogation SECM using [Ru(NH₃)₆]^2+/3+ coupled with X-ray photoelectron spectroscopy (XPS) identified the Pt⁴⁺-enriched surface of PtO_x with a bilayer structure to give more efficient regeneration of Pt(0) under the shorter reversal interval. The in situ SECM complemented bulk electrolysis and XPS to demonstrate that ClER on Pt(0) and OER on PtO_x primarily determine the CE of ClER, in agreement with a kinetic model. The descriptive role of surface Pt/PtO_x ratio rationalized the enhanced selectivity for ClER upon the polarity switching, being independent on a scaling relationship. The current reversal (not allowed to IrO₂ electrodes) also alleviated calcareous scale deposit in the electrolyte with hardness.

sLex expression in invasive micropapillary breast carcinoma is associated with poor prognosis and can be combined with MUC1/EMA as a supplementary diagnostic indicator

OBJECTIVE

Mucin 1 (MUC1/EMA) and sialyl Lewis X (sLex) indicate polarity reversal in invasive micropapillary carcinoma (IMPC). The purpose of this study was to evaluate the expression of MUC1/EMA and sLex and to assess their diagnostic and prognostic value in patients with IMPC.

METHODS

The expression of sLex and MUC1/EMA in 100 patients with IMPC and a control group of 89 patients with invasive ductal carcinoma not otherwise specified (IDC-NOS) were analyzed with IHC. Fresh tumor tissues were collected from patients with IMPC or IDC-NOS for primary culture and immunofluorescence analysis.

RESULTS

The rate of nodal metastasis was higher in patients with IMPC than those with IDC-NOS, and IMPC cells tended to express more sLex and MUC1/EMA in the cytomembranes (the stroma-facing surfaces of the micropapillary clusters) than IDC-NOS cells. In IMPC, high cytomembrane expression of sLex, but not MUC1/EMA, indicated poor prognosis. In addition, among the 100 patients with IMPC, 10 patients had sLex+/EMA- expression patterns, and 8 patients had sLex-/EMA+ expression patterns. The primary IMPC cells were suspended, non-adherent tumor cell clusters, whereas the primary IDC cells were adherent tumor cells. Immunofluorescence analysis showed that MUC1/EMA and sLex were co-expressed on the cytomembranes in IMPC cell clusters and in the cytoplasm in IDC-NOS cells.

CONCLUSIONS

sLex can be used as a prognostic indicator and can be combined with MUC1/EMA as a complementary diagnostic indicator to avoid missed IMPC diagnosis.

Structural characterization of Myxococcus xanthus MglC, a component of the polarity control system, and its interactions with its paralog MglB

The δ-proteobacteria Myxococcus xanthus displays social (S) and adventurous (A) motilities, which require pole-to-pole reversal of the motility regulator proteins. Mutual gliding motility protein C (MglC), a paralog of GTPase-activating protein Mutual gliding motility protein B (MglB), is a member of the polarity module involved in regulating motility. However, little is known about the structure and function of MglC. Here, we determined ∼1.85 Å resolution crystal structure of MglC using Selenomethionine Single-wavelength anomalous diffraction. The crystal structure revealed that, despite sharing <9% sequence identity, both MglB and MglC adopt a Regulatory Light Chain 7 family fold. However, MglC has a distinct ∼30° to 40° shift in the orientation of the functionally important α2 helix compared with other structural homologs. Using isothermal titration calorimetry and size-exclusion chromatography, we show that MglC binds MglB in 2:4 stoichiometry with submicromolar range dissociation constant. Using small-angle X-ray scattering and molecular docking studies, we show that the MglBC complex consists of a MglC homodimer sandwiched between two homodimers of MglB. A combination of size-exclusion chromatography and site-directed mutagenesis studies confirmed the MglBC interacting interface obtained by molecular docking studies. Finally, we show that the C-terminal region of MglB, crucial for binding its established partner MglA, is not required for binding MglC. These studies suggest that the MglB uses distinct interfaces to bind MglA and MglC. Based on these data, we propose a model suggesting a new role for MglC in polarity reversal in M. xanthus.

Overexpression of β1 integrin contributes to polarity reversal and a poor prognosis of breast invasive micropapillary carcinoma

Invasive micropapillary carcinoma (IMPC) of the breast is a highly aggressive breast cancer. Polarity reversal exemplified by cluster growth is hypothesized to contribute to the invasiveness and metastasis of IMPC. In this study, we demonstrate that levels of β1 integrin and Rac1 expression were greater in breast IMPC than in invasive breast carcinoma of no specific type and paraneoplastic benign breast tissue. We show that silencing β1 integrin expression using the β1 integrin inhibitor AIIB2 partially restored polarity in IMPC primary cell clusters and downregulated Rac1. Thus, overexpression of β1 integrin upregulates Rac1. Univariate analysis showed that overexpression of β1 integrin and Rac1 was associated with breast cancer cell polarity reversal, lymph node metastasis, and poor disease-free survival in IMPC patients. Multivariate analysis revealed that polarity reversal was an independent predictor of poor disease-free survival. These findings indicate that overexpression of β1 integrin and the resultant upregulation of Rac1 contribute to polarity reversal and metastasis of breast IMPC, and that β1 integrin and Rac1 could be potential prognostic biomarkers and targets for treatment of breast IMPC.

Misaligned and Polarity-Reversed Faces Determine Face-specific Capacity Limits

Previous research using flanker paradigms suggests that peripheral distracter faces are automatically processed when participants have to classify a single central familiar target face. These distracter interference effects disappear when the central task contains additional anonymous (non-target) faces that load the search for the face target, but not when the central task contains additional non-face stimuli, suggesting there are face-specific capacity limits in visual processing. Here we tested whether manipulating the format of non-target faces in the search task affected face-specific capacity limits. Experiment 1 replicated earlier findings that a distracter face is processed even in high load conditions when participants looked for a target name of a famous person among additional names (non-targets) in a central search array. Two further experiments show that when targets and non-targets were faces (instead of names), however, distracter interference was eliminated under high load—adding non-target faces to the search array exhausted processing capacity for peripheral faces. The novel finding was that replacing non-target faces with images that consisted of two horizontally misaligned face-parts reduced distracter processing. Similar results were found when the polarity of a non-target face image was reversed. These results indicate that face-specific capacity limits are not determined by the configural properties of face processing, but by face parts.

A physiological mechanism for Hebb's postulate of learning

Hebb's postulate of learning envisages that activation or inactivation of extant synaptic contacts in plastic neural networks depends on the synchronous impulse activity of pre- and postsynaptic nerve cells. The physiological mechanism proposed here for this process posits that at synapses acting according to Hebb's postulate, the receptors for the neurotransmitter are eliminated from the postsynaptic membrane by the transient reversals of the sign of membrane polarization that occur during action potential impulses in the postsynaptic cell. But, since the release of neurotransmitter drives the membrane potential of the synaptic zone towards a level about half-way between the negative-inside resting potential and the positive-inside action potential, it would follow that the membrane patches surrounding the receptors of a synapse whose activity has contributed to setting off the postsynaptic impulse would be spared the full extent of the noxious polarity reversal. This mechanism can account for a neurophysiologically documented example of the operation of Hebb's postulate, namely the plasticity of the connections between fourth- and fifth-order neurons in the visual cortex of cats.